1. Technical Field
The present invention relates to reduction of tinnitus suffering. More particularly, examples of the invention provide a novel method and device for optimization of maskings for the reduction of tinnitus suffering.
2. Description of Related Art
The American Tinnitus Association defines tinnitus as the term used generally to describe noises that are perceived in the absence of any true external source. Although some people suffer from what is called “objective tinnitus,” in which there is an audible source for the noise that the person hears that can also be heard by another person, most people who suffer from tinnitus have “subjective tinnitus,” in which the noises heard are not audible by anyone else.
Perhaps the most common form of tinnitus is described as a “ringing” in the ears, which may take on a specific tone, that is, an amplitude at a specific frequency, much like a tone generated by a tuning fork; however, tinnitus sufferers can hear other noises, which may be characterized by hissing, whooshing, buzzing, popping, or other terms. The volume of the noise may vary with head motion, physical activity, degree of consciousness, or other factors. For example, some people perceive a spike in a background level of tinnitus during the time that they begin to fall asleep or just after waking. Tinnitus can be associated with hearing loss, although this is not always the case, and can also be associated with medical conditions such as Meniere's disease or other auditory diseases, although this is also not always the case.
Tinnitus is a common ailment. It affects both adults and children. Currently, there is no definitive understanding of any genetic predisposition to tinnitus, although there are genetic predispositions to certain syndromes and medical conditions that are often associated with tinnitus. Many famous people have been afflicted with tinnitus, including reportedly musicians Neil Young, Pete Townshend, comedian David Letterman, and former president Ronald Reagan.
It is estimated that about 20 percent of all people suffer some degree of tinnitus (http://www.bixby.org/faq/tinnitus/discover.html). The National Institute on Deafness and Other Communication Disorders (NIDOCD) (which is part of the National Institutes of Health) reports that over 12 million Americans suffer from tinnitus. The American Academy of Otolaryngology reports that 36 million Americans suffer from tinnitus. The American Tinnitus Association and Society for Neuroscience report that over 50 million Americans are afflicted with this condition. Dr. Pawel Jastreboff reported that over 4 million Americans suffer significantly from tinnitus.
It has been reported that in a study of over 1544 tinnitus patients, over three-quarters of these patients characterized tinnitus sounds as being “tonal” with an mean degree of loudness of 7.5 on subjective 10 scale (http://www.bixby.org/faq/tinnitus/discover.html). Of the remainder 21 percent characterized the sound with a mean loudness of 5.5. For comparison, an externally generated noise source was 7.5 dB above threshold, and a majority of patients could have their tinnitus masked by sounds that were 14 dB above threshold. Most persons described their tinnitus as being located in both ears, but others described it as emanating from the head, or only one ear. The American Tinnitus Association reported that there was no statistical correlation, however, between the measured level of tinnitus and the sufferers perception of the severity of the tinnitus. Tinnitus is a very personal and subjective experience.
Noise exposure has been identified as a source for causing tinnitus, particularly heavy construction equipment, leaf blowers, jet engines, rock concerts, and similar sources, but in a study of 1687 tinnitus patients, no known cause was identified for 43 percent of the cases (http://www.bixby.org/faq/tinnitus/discover.html). It is often very difficult to determine the source of tinnitus and the mechanisms involved are not completely or even well understood in many cases. There is some evidence to suggest that specific foods may cause tinnitus, including red wine and other alcohol, cheese, caffeine, tonic water, and chocolate, and there have been reported similarities to foods that cause migraines. Artificial sweeteners such as aspartame have been claimed (but perhaps not proven) to be associated with tinnitus, and aspirin is associated with some cases of tinnitus (although there is less agreement about the effects of other non-steroidal anti-inflammatory NSAID drugs). Other drugs, such as oral contraceptives and nicotine, may also be associated with bringing on or worsening cases of tinnitus. The NIDOCD reports that over 200 medicines are associated with causing tinnitus.
Various diseases are also associated with tinnitus, including lyme disease, acoustic neuromas, glomous tumors (which may cause pulsatile tinnitus), and otosclerosis. Medical conditions may also contribute to tinnitus, including ear wax build up, ear infections, suffering from a flu or other virus or other infection, TMJ syndrome, certain tumors, fibromyalgia, high blood cholesterol levels, and hypertension. Injuries such as head trauma and dental procedures have been associated with tinnitus. Some people have indicated that mercury amalgam tooth fillings may be associated with tinnitus, but these claims are at best controversial. Other conditions such as stress, fatigue, and diet have also been associated with episodes of tinnitus.
Various medical tests and procedures have been created for determining a diagnosis of tinnitus; however, tinnitus sufferers generally do not need specific tests to diagnose that they are hearing noises. Such tests may be helpful in identifying particular types of tinnitus, but may not be helpful in addressing the symptoms of the condition, that is, such tests may not be helpful in alleviating, mediating, or halting the sensation of hearing noises.
The treatments for tinnitus are quite varied, with no true cure for the condition. Some drug treatments include the use of anti-depressants and anti-anxiety medications. Tinnitus sufferers may become depressed or feel tense from the constant noise that they hear. The medications may help sufferers to cope with the tinnitus but do not cure the condition, although some reports have indicated that these medications may reduce the level of tinnitus, perhaps with some physiologically reasonable rationale (that is, other than a placebo effect). Some of the drugs in these classes of medicines may also increase tinnitus.
Dr. Robert M. Johnson et al. reported on a double-blind study with a placebo control for administering alprazolam (marketed as Xanax) in which over three-quarters of subjects reported a reduction in tinnitus of at least 40 percent. This compared well to only 5 percent of the placebo subjects with an improvement in tinnitus. Xanax, and other drugs in this class, can be addicting and have other side effects, and so this treatment has important deficiencies. Other drug treatments reported in the literature have included anti-convulsants, local anesthetics, anti-arrhythmics, histamine, anti-histamine, and diuretics. Each of these carries potential side effects and none is entirely effective.
Herbs and vitamins have also been explored to alleviate tinnitus. Some evidence has suggested a possible vitamin B-12 deficiency in some tinnitus sufferers. Vasodilators such as niacin or Gingko biloba have been tested. The results may be described as inconclusive, with some theoretical justification for believing that vasodilators may make tinnitus worse in certain patients. Also high doses of niacin are associated with flushing and also potentially liver damage, and Gingko biloba is a blood thinner, which may not be appropriate for some patients. Zinc has also been suggested as possibly beneficial, but high levels of zinc may interfere with copper absorption. Magnesium has been tested on tinnitus sufferers that were exposed to high levels of impulse noises (for example, explosions). Hearing loss was reduced by the administering of magnesium, however the effect on tinnitus was not entirely clear.
Other efforts to reduce or halt tinnitus include hypnosis, chiropractic adjustment, biofeedback, relaxation, counseling, self-help group therapy, acupuncture, hearing aids (used more to improve the signal-to-noise ratio of people talking as compared to the level of tinnitus than to reduce the level of tinnitus), oxygen therapy, and electrical stimulation of the ear. None of these methods have established clinically verifiable repeatable effectiveness on a broad spectrum of tinnitus sufferers. It is noteworthy that severing the auditory nerves of a tinnitus sufferer, which leaves the sufferer completely deaf, may not alleviate tinnitus. If tinnitus is originating in the brain, the sufferer may still continue to hear the sounds, even though he or she cannot hear anything else.
One of the more interesting approaches to addressing tinnitus is described as “auditory integration training” (AIT). Studies by Dr. Guy Berard (reported in Hearing Equals Behavior) have reported the method of listening to music that is altered such that high and low frequencies are randomly shifted in and out. The course of treatment is reported as 30 minute sessions, twice per day, for 10 days. Two different devices have been constructed for delivering the Berard AIT. At this time, reports suggest that there is no scientifically proven theory for why AIT should work but it is reported to be potentially effective. Some concerns have been indicated that AIT treatments may be given at uncomfortably loud volume levels, which could worsen tinnitus. Several AIT organizations are currently in operation in the United States of America. It has been reported that professional memberships in at least one organization have been suspended pending FDA approval of the AIT devices. Similarly, sound therapy can be offered to a tinnitus sufferer, which generally involves listening to constantly alternating sounds of high and low tone. Simultaneously, low frequency sounds are progressively removed so the ear is introduced to higher and higher frequencies. Reduction in tinnitus is reported as occurring in as little as 24 hours or as long as 14 months. In tinnitus retraining therapy, reported results may take as long as 18 months.
Another approach to treating tinnitus is to mask the tinnitus with other noises. A common noise used for this purpose is white noise, akin to radio static; however, many other sources of noise can be used including filtered white noise (that is, white noise that is altered by mathematical filters to have different spectral properties), rain, waterfalls, surf, airplane cabin sounds, and others. The concept of masking is to provide the brain with an external source of noise that serves as a distraction from the tinnitus. A common way to describe this is that the brain would rather listen to real noises than imaginary noises, and thus these sounds can reduce tinnitus, sometimes greatly and even all the way to a complete halting of the imagined noise. The trade-off that tinnitus sufferers must choose is whether it is easier to listen to the distraction noise or their tinnitus; however, in some cases, tinnitus sufferers have noted that by applying masking sounds, when the sounds are removed, the tinnitus does not return, or does not return for a significant amount of time, or continues but at a reduced level.
Products exist currently that serve the purpose of tinnitus masking. For example, Ambient Shapes, Inc. of Hickory, N.C. sells the Marsona Tinnitus Masker, which offers over 3000 alternative masking noises, for approximately $250. The Sharper Image company of San Francisco, Calif. offers two tinnitus masking devices, the Portable Sound Soother and the Digital Sound Soother, for $120 and $170, respectively. The devices offer alarm clocks and three sources of noise: white noise, seaside, and countryside. Additional independent sounds such as fog horns and owls are also included with independent volume control.
A deficiency of the masking approach is in finding the right noise to provide to the tinnitus sufferer. A trial-and-error process can be conducted by a third person, such as a hearing professional (a medical doctor trained as an otolaryngologist or a medical assistant), to determine which of a collection of noises might have the best effect (known as residual inhibition). This approach is much like the process that is used commonly to adjust eyeglass prescriptions, in which a third person allows an eyeglass wearer to look though alternative lenses and asks if their vision is better or worse, converging over a series of alterations on an optimum. In tinnitus retraining therapy, the process is reported to require extensive one-on-one time with highly trained professionals (although the process may not require masking noises but instead “enriching” the sound background, coupled with counseling). This is a deficiency that is addressed by the current invention.
Furthermore, unfortunately, the physics of hearing and of tinnitus, which may derive from brain activity and not from the auditory nerve, is not as simple as the physics of visual acuity. It is not true that a person can simply follow a progression of alternative forms of noise and arrive at an optimal form that provides maximum residual inhibition. In fact, the optimal static form may be a combination of other noises, not any single noise. Furthermore, with the idea of transforming noises presented to the tinnitus sufferer, as described above, the challenge becomes one of finding not just a best noise source to use, but a best noise source that changes over time. In addition, what may be the optimal source to use for a tinnitus patient on a given day or in a given background setting may not be optimal on another day or in a different background setting. These deficiencies are also addressed by the current invention.